Quartz products are widely used in high-tech fields, such as electronic materials, silicon dioxide film materials, silicon fiber communication cable materials, etc. These high-performance materials have strict requirements on the quality of raw materials and require high-purity silicon dioxide.
The impurities that affect the purity of quartz mainly include clay ores and iron oxides that contain aluminum elements. Among them, iron oxides mainly include iron ore and limonite. Since the hardness of these minerals is close to that of quartz, it is difficult to achieve monomer dissociation during the crushing process, and most of them are conjoined with quartz particles. Therefore, This type of impurity can be effectively removed by magnetic separation.
When performing magnetic separation, the wet strong magnetic separation method is generally used for primary separation, which can remove hematite, limonite, and hydrobiotite including conjoined particles and inclusions as much as possible. In addition, in order to improve the separation effect, attention should be paid to the ore concentration, magnetic field strength and flushing water volume during magnetic separation.
As mentioned above, clay minerals are also one of the impurities that affect the purity of quartz. When minerals such as montmorillonite, hydrobiotite and illite are crushed and graded to deslime the ore, part of the clay impurities can be removed with mudification, but there are still some sheet-like structural components that do not have hydration characteristics. When dealing with such impurities, the mica flotation process can be used for separation. When the mica flotation separation method is used, it can generally be divided into two methods according to the properties of the mineral raw materials:
Method 1: In the alkaline pulp, an anionic collector is used to directly select the quartz through positive flotation, and the mica enters the tailings.
Method 2: In acidic pulp, cationic collectors are used to select mica through reverse flotation, and the tailings quartz is recovered.
After magnetic separation and flotation separation, the aggregate particles with more impurities in the raw ore have been basically removed, but there are still some harmful components or inclusions on the quartz particles. In order to remove such harmful impurities, acid leaching of quartz is required. Because quartz is acid-resistant (except HF), others will be dissolved by acid into soluble compounds, separated from the quartz particles in the liquid, and then removed by solid-liquid separation and water washing. Since most of the harmful components exist in the form of mineral aggregates, mixed acid acid leaching can be used, and the synergistic effect produced has a stronger effect of dissolving impurities.
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